Police have said they do not believe Miss Hachem was the intended target and have dismissed suggestions it was a racist or terrorist attack.

One theory being investigated is that the gunman had been aiming at a carwash behind where Miss Hachem was standing.

A video that emerged on social media appeared to show a car cruising slowly past the teenager on King Street in central Blackburn before she suddenly falls to the ground.

Forensics specialists in white suits could be seen examining the Quick Tyre and Quick Shine car wash business, which also seemed to have been struck by bullets.

Police were examining a car was close to the scene of the shooting

A green Toyota Avensis car, which police believe was used in the attack, was found abandoned a short distance away.

Three men, all in their 30s, were arrested by Lancashire Police on suspicion of murder and remained in custody for questioning.

A spokesman for Lancashire Police said they were aware of a number of videos circulating across social media and were asking people to report them to the police. Det Supt Andy Cribbin said: “Our determination to find who was responsible for the death of Aya continues and we have a large team of detectives working on the inquiry. “We know that a lot of people have expressed their support for the police investigation and I would like to thank them for that.

“However, we know of a number of videos of the incident are on social media and it is important that people formally report these to us as they are potential evidence.

“We would also ask people, even if they are well intentioned, not to share these videos out of respect for Aya and her family.”

It has also emerged Miss Hachem's family fled to Britain from war torn Lebanon ten years ago after her father, Ismael, was shot.

According to family friends, he was shot in crossfire in Lebanon and moved to England hoping for a new life, spending nine years as an asylum seeker, before eventually being granted British citizenship last year. Tributes continued to pour in to Miss Hachem, who had just completed the second year of a law degree at Salford University and was an active charity and community campaigner.

Described as a “remarkable young woman” she dreamed of becoming a solicitor after she had graduated.

Her parents Samar and Ismael said: "She was the most loyal, devoted daughter who enjoyed spending time with her family, especially her brothers and sisters Ibraham, Assil and Amir.

"We, her parents, are absolutely devastated by her death and would like to take this opportunity to plead with any members of the public who may have any information however small that may bring those responsible to justice.”

A tribute from Blackburn Central High School, described her as a where she had been an award model student who was hardworking and determined to be the very best she could be.

A statement released by the school read: "She had lots of friends and was involved in helping others by organising charity events.

"A beautiful young girl who fled her home country in search for a better life in the UK.

"At school she embraced every opportunity and was one of the students whose achievement we have celebrated on numerous occasions, an example of what is possible"She will always be remembered for her diligence, her beautiful character and her humble nature."

Aya Hachem had dreamed of one day becoming a solicitor

Aya was also one of the youngest ever trustees for The Children's Society, a charity known for its research into the well-being of children.

Bosses at the organisation have paid tribute to Aya in the wake of her death.

Chief executive Mark Russell said: "We are deeply saddened to learn of the death of one of our young trustees, Aya Hachem.

"She was a truly remarkable young woman, and an inspiring voice for children and young people. Our thoughts are with her family at this awful time."

Dr Janice Allan, dean of Salford Business School said: "Aya Hachem was a very popular and promising second year student whose contribution went beyond the classroom.

"Our thoughts are with her family and friends at this difficult and distressing time."

Aya and her family were also closely involved with Blackburn's asylum seeker and refugee community.

Community leaders from across Lancashire also tribute to the 19-year-old, who was described as being full of ambition to do good.

A statement on behalf of senior clergy of the Diocese of Blackburn, said: ”Shock and horror are the words that come to mind. We as leaders of the Church of England in Lancashire affirm our strong belief that violence should not have any place in our community.

"We express our heartfelt sympathy and support for Aya's family and friends as they face this terrible and unexpected news, assuring them of our love and prayers."

Several fundraising and memorial pages that were set up in the wake of her murder had raised tens of thousands of pounds